A follow-up to the book "Unnatural Acts: Critical Thinking, Skepticism and Science Exposed!" by Robert Todd Carroll, creator of The Skeptic's Dictionary. The blog will offer irregular postings about cognitive biases, logical fallacies, and illusions.

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Monday, December 26, 2011

ad hoc hypothesis

In science, an ad hoc
hypothesis is an assumption made in response to facts that are
inconsistent with a theory in order to prevent the theory from being
falsified. By extension, an ad hoc hypothesis is any assumption made to
save a claim from being refuted. What are often called ad hoc hypotheses
might better be referred to simply as rationalizations.One
of the more important ways of testing a scientific theory is to deduce
observations that should occur under specified conditions if the theory
is correct. An experiment may create those conditions and if the
predicted observations occur, the theory is said to be confirmed.
Experiments that confirm a theory should be replicable. If the predicted
observations do not occur and it is determined that the theory cannot
be correct if they do not, then the theory is falsified. Likewise, if
experiments fail to replicate confirmations and it is determined that
the theory cannot be correct if replication doesn't occur, then the
theory is said to be falsified. If a new fact is discovered that is
inconsistent with the theory, the fact must be accommodated. The theory
might be tweaked or it may be preserved by hypothesizing another fact
that would make the first fact consistent with the theory. Or, the fact
might prove the theory false.

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When
William Hershel discovered the planet Uranus in 1781 by telescopic
observation, it was also discovered that the new planet’s orbit was
different from what it should have been according to Newton’s laws. The
orbit of Uranus was an anomaly: a phenomenon that apparently did not fit
with the Newtonian paradigm. Some scientists may have thrown up their
hands and said: “See, Newton was wrong! Hah!” Others may have offered
the ad hoc hypothesis that the anomalous orbit was caused directly by
God. Uranus has a different kind of orbit than the other planets because
God is working a miracle—suspending the laws of nature—perhaps to
demonstrate his power and existence to us. But most scientists set to
work to solve the puzzle. The simplest solution was to posit another
planet beyond the orbit of Uranus whose gravitational force was
affecting the planet’s orbit. This hypothesis could be independently
tested. Its size and orbit could be calculated based on how much it
perturbed the motion of Uranus. Thus was Neptune discovered. When the
math for Neptune’s orbit didn’t work in accordance with Newton’s laws,
it was proposed that still another planet awaited discovery. The object
known as Pluto gave astronomers the data to show that Neptune did, after
all, orbit in accordance with Newton’s laws. Both of these hypotheses
could be independently tested, albeit with some difficulty given the
state of knowledge and technology at the time.

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When
Alfred Wegener proposed his theory of continental drift in 1912 against
the prevailing theory that the Earth was formed by cooling from a
molten state and contractions, he could not explain how continents move.
It was suggested that gravity was the force behind the movement of
continents, though there was no scientific evidence for this notion. In
fact, scientists could and did show that gravity was too weak a force to
account for the movement of continents. Alexis du Toit, a defender of
Wegener’s theory, argued for radioactive melting of the ocean floor at
continental borders as the mechanism by which continents might move.
“This ad hoc hypothesis added no increment of plausibility to Wegener’s
speculation,” wrote Stephen Jay Gould (Ever Since Darwin. W.W. Norton & Company.1979, p. 163).

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George
Dillman claims that he and his top students can knock out people by
manipulating some sort of subtle energy called qi (chi or ch'i,
pronounced chee). When 8th degree black belt Leon Jay failed to move
Luigi Garlaschelli with qi, Dillman offered the following ad hoc
hypotheses. 1. Garlaschelli is a total non-believer and you must believe
you can be knocked out by qi for the power to work. 2. Garlaschelli
might have had one big toe pointing upward and the other pointing
downward. If so, the power won't work. 3. Maybe Garlaschelli wasn’t
knocked out because his tongue was "in the wrong position." While
Dillman's hypotheses seem like obvious rationalizations, they have the
merit of being empirically testable to a degree. Qi remains undetectable
by science's most refined measuring instruments, but we can at least
test the toe and tongue position claims. If the no-touch knockout
doesn't work even when the toes and tongues are aligned the way Dillman
wants them, we'll at least know that these hypotheses are false. On the
other hand, if Jay or Dillman knocked over Garlaschelli without touching
him when his toe and tongue were aligned, we'd have evidence in favor
of the qi hypothesis.

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Defenders
of alleged psychic Edgar Cayce provided a classic rationalization to
explain away their hero’s failures. For example, Cayce and a famous
dowser named Henry Gross set out together to discover buried treasure
along the seashore and found nothing. Their defenders suggested that
their psychic powers were accurate because either there once was a
buried treasure where they looked but it had been dug up earlier, or
there would be a treasure buried there sometime in the future.

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Some
scientists think they have evidence for the existence of ESP. They
predict that in card-guessing experiments where there are five choices,
guessing correctly 20% of the time is expected by random chance.
Proponents of ESP maintain that if a person has psychic ability, she
will select unseen cards correctly at a rate that is statistically
significant, i.e., a rate not likely due to random chance.

Rather
than admit that an experiment could not be duplicated because the ESP
it was supposed to confirm couldn’t be confirmed, experimenters have
been known to blame the hostile thoughts of onlookers for unconsciously
influencing the outcome. Of course, if this ad hoc hypothesis is taken
seriously, then no experiment on ESP or PK (psychokinesis) can ever
fail: Whatever the results, one can always say they were caused by
paranormal psychic forces, either the ones being tested or the hostile
ones not being tested. The "hostile energy" hypothesis can't be
independently tested. (Some dowsers who fail tests of their art also
appeal to the hostile energy of skeptics interfering with their powers.
And some practitioners of facilitated communication
who fail scientific tests of their ability are excused because the
testing made them nervous and unable to get the communication from their
clients.)

Psi-missing
is an ad hoc hypothesis invented by parapsychologists to explain away
failures to demonstrate ESP. The tests usually involve trying to use ESP
to identify various targets, such as Zener cards,
pictures, etc. which are hidden from direct view of the subject. The
failure to do better than would be expected by chance is explained away
as due to unconscious direction to avoid the target.

Psychic drift is the entry of unintended non-target data into the psychic transmission or reception path during a psi
experiment. Psychic drift may account for some telepathic subjects
guessing the wrong card, photo, video clip, etc. They're getting
information inadvertently sent from a card game in Las Vegas, a psi
experiment in Edinburgh, or a television program from an apartment in
Moscow. Or, psychic drift could be another ad hoc hypothesis used by
parapsychologists to explain away psi failure.

Physicist
John Taylor explained that the reason the children he was studying for
their psychokinetic powers could bend forks and spoons with their minds
only when nobody was looking was because of "the shyness effect." The
children weren't shy; paranormal phenomena are. Taylor hypothesized that
paranormal phenomena have an aversion to scrutiny.

When
a psychic dowser was unable to distinguish bottles of regular water
from those he claimed he had energized with healing properties, he
hypothesized that his magic water had energized all the bottles of water
in the room. You can view this rationalization on Nova's "Secrets
of the Psychics" with James Randi. The magic water hypothesis is
reminiscent of the claim that several copies of the shroud of Turin
exist because the original has the magic property of transferring its
image to nearby cloths.

Ingo Swann, an advocate of remote viewing,
claimed that he saw a 30,000 ft. mountain range on Jupiter on an astral
voyage when there is no such thing. Swann, in a lovely ad hoc
hypothesis, now claims that astral travel is so fast that he probably
wasn't seeing Jupiter but another planet in another solar system! There
really is a big mountain out there on some planet in some solar system
in some galaxy.

___

Dorothy
Martin led a small UFO cult in the 1950s. She claimed to get messages
through automatic writing from extraterrestrials known as The Guardians.
Like the Heaven’s Gate cult forty years later, Martin and her
followers—known as The Seekers or The Brotherhood of the Seven Rays—were
waiting to be picked up by a spaceship. In Martin’s prophecy, her group
of eleven would be saved just before the total destruction of Earth by a
massive flood on December 21, 1954. When the day of reckoning came and
went, it became evident that there would be no flood and that the
Guardians were no-shows. Martin allegedly became euphoric. She claimed
that she’d received a telepathic message from the aliens explaining that
God had decided to spare the planet as a reward for their great faith.
All but two of her merry little band failed to recognize that this new
revelation was rationalized rubbish. They not only stuck with her
despite the absurd improbability of her claim; their devotion actually
increased. (Some believers in faith healing and intercessory prayer
claim that failures are due to people not having enough faith.)

___

Believers in biorhythms
claim that our daily lives are significantly affected by rhythmic
cycles overlooked by scientists who study biological rhythms. When
confronted with cases that conflict with the predictions of biorhythms,
defenders claim that some people are arrhythmic. Another favorite ad hoc
hypothesis concerns the claim that biorhythms can predict with 95%
accuracy the sex of an unborn fetus. When the prediction was wrong that
was because the fetus was a homosexual and homosexual fetuses have
indeterminate sex identities!

___

One of my favorite ad hoc hypotheses comes from Philip Henry Gosse who argued in Creation (Omphalos): An Attempt to Untie the Geological Knot (1857)
that God created the world a few thousand years ago complete with
fossils. Another favorite comes from a defender of Nostradamus, who
argued that Nostradamus predicted the Challenger space shuttle disaster
on January 28, 1986. The allegedly predictive quatrain reads, in part,
"From the human flock nine will be sent away." To account for the fact
that there were only seven on board, it was posited that Christa
McAuliffe was pregnant with twins.

Another
example of providing a whopper of a rationalization involves Uri
Geller. In 1973 Geller appeared on the Johnny Carson "Tonight Show" and
was supposed to demonstrate his ability to bend spoons with his thoughts
and identify hidden objects, but he failed to even try. He squirmed
around and said something about how his power can't be turned on and
off, and that he didn't feel strong right then. Actually, James Randi
had worked with Carson's producer to change the spoons and metal items
that Geller planned to use, as there was a suspicion that Geller likes
to work (i.e., soften) his metals before his demonstrations, as would
any careful conjurer.

Psychologist
Ray Hyman provides the most dramatic example of rationalization that
I've ever come across. A chiropractor hypothesized that randomized,
double-blind, controlled tests of causal claims "don't work" rather than
admit that his belief in applied kinesiology had been falsified by such a test.

___

Offering
alternative explanations for something is not the same as proposing an
ad hoc hypothesis. If I say of someone who recovers from an illness
after going to an energy healer that she might have recovered had she
not consulted any healer and that the illness might have resolved itself
on its own, I am not trying to save my hypothesis that energy healing
is placebo medicine by offering an ad hoc hypothesis. Offering plausible
alternatives is not the same as rationalizing to save a belief,
especially when the plausible alternative has been demonstrated in many
independent tests.

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